Does Finding Nemo have a post-credit scene?

Yes, Finding Nemo has a post-credits scene — and it also has a scene at the very start of the credits, so the film gives you two reasons not to leave.

The first arrives immediately after 'The End'. Dr. Sherman is complaining to his assistant Barbara about the AquaScum 2003, the automatic tank cleaner he installed, and discovers the tank is empty. The film then cuts to the Tank Gang — Gill, Bloat, Peach, Gurgle, Bubbles, Deb and Jacques — bobbing in the harbour, each still sealed inside his or her own plastic bag, having escaped the office but not the bags. Gill's flat 'Now what?' is the punchline the entire escape plot has been building to. From there the credits proper roll, scored with Robbie Williams' cover of Beyond the Sea, with characters from across the film swimming through the titles.

After the credits finish, two things play. First a dedication card to Glenn McQueen, the Pixar supervising animator who died of melanoma in October 2002 during production; the studio later named Lightning McQueen in Cars after him. Then the actual stinger: the small green fish who was dragged along to the sharks' support-group meeting is drifting in the dark when the anglerfish looms out of the black towards it — and the tiny fish eats the anglerfish. It is about four seconds long and it is the only genuinely post-credits gag in the film.

Is it worth staying for? The Tank Gang scene, yes, unequivocally — without it their entire storyline has no ending, which is precisely why Finding Dory went back and gave them a proper one in its own post-credits scene thirteen years later. The anglerfish gag is a small bonus rather than a reason to sit through eight minutes of credits, but it is the last laugh in the film.